package nimble.maxwoods.regx;/**
 * @description:
 * @authoer: Max Woods
 * @create:2018/7/2 15:51
 **/


import java.util.HashSet;
import java.util.Set;

/**
 *@auther: Max Woods
 *@create:2018/7/2 15:51
 **/
public class SetTest {

    public static void main(String[] args)
    {
        Set<String> urls=new HashSet<>();
        boolean s=urls.add("a");
        s=urls.add("a");
    }
}
